Fuse



N. C. HUSTED April 15, 1930.

FUSE

Fild July 24 Patented Apr. 15, 1930 NORRIS C. HUSTED, OF NILES, OHIO FUSE Application filed July 24, 1925. Serial No. 45,813.

This invention relates to electric fases and more particularly to those of the so called expulsion type wherein the gases and Vapors formed at the time the fuse blows, and which result from the volatilization of the fuse wire, are expelled with such force as to extinguish the are which tends to form along the line of the fuse wire, and also to actually expel a portion of the severed wire from the casing so as to nsure breakage of the current.

Because of the fact that the fuse wire is of low melting point and is almost entirely enclosed within the fuse casing it tends to become unduly heated even during normal operation with the result that it is partially volatilized and a metallic coating deposited along the inner wall of the casing between the fuse terminals. Such a coating is liable to short circuit the fuse wire. In order to 0 prevent this premature heating of the wire it is necessary to provide means for ventilating the casing and an object of this invention is to provide an eXpulsion fuse which is so constructed and arranged that the entire casing is open to ventilat-ion.

A further object is to provide a devce of the type set forth which is so constructerl that, while the fuse casing is open to Ventilalion throughout the entire length of the fuse wire; it is provided with means which are automatically operable upon blowing of the fuse to close one end of the casing so as to expel the gases and Vapors formed at the time of blowing in the desired direction with suiiicient Velocity to extinguish any arc which may tend to form.

A still further object is to provide a device of the type set forth which willbe simple in Construction, easy and cheap to manufacture and assemble and positive in operation.

These and other objects which will appear obvious to those skilled in this particular art are accomplished by means of this invention, one emhodiment of which is shown for the purposes of illustration in the accompanying drawngs in which Figur-e 1 is a longitudinal sectional View through the center of a renewable cartridge fuse constructed in accordance with one form of this invention'and Fig. 2 is a perspectve View of a valve disc for use in the Construction shown in Fig. l.

The illustrated embodiment of this invention includes the usual cylindrical Cartridge fuse body member or casing 5 which is open from end to end. A metallic sleeve-like contact member 6 is threaded to one end of the fuse casing 5 and is adapted to engage the well known socket members in the usual manner. The sleeve 6 constitutes one terminal for the ordinary fuse wire 7 which is secured thereto in any desired manner.

A similar metallic contact member 8 is threaded upon the other end of the casing and a valve plug 9 is threaded into the projecting end of the sleeve 8. An a *in 10, formed upon the valve plug 9 and extending inwardly of the casing 5, is adapted to have the other end of the fuse wire Secured thereto by means of a clamping plate ll or any other desired means.. A valve disc 12 is loosely received in a Valve chamber 13 forned in the end of the plug 9 and the disc is re tained in place by a cap 14, which is Secured to the valve plug and which has a ventilating opening 15 leading into the valve chamber. The valve plug 9 has a similar ventilating opening 16 connecting the valve chamber with the interier of the fuse casing 5.

The Valve disc has radial slots 17 in its lower face communicating with axially extending slots 18 in the periphery of the disc so that when the fuse is in its normal upright position on a panel the disc will ordinarily be in the position shown in Fig. l and an unobstructed path for the passage of ventilating air will be provided through the fuse casing, the opening 16, the slots 17 and 18, the valve chamber l3 and the opening 15 in the valve cap to ,the atmosphere.

If during normal operation the interier of the casing or the fuse wire should become heated the increase in the temperature of the air within the casing will cause the same to rise and pass out toward the casing through the valve chamber, fresh air being drawn in through the lower open end. Any premature heating of the fuse wire 7 and the resulting partial volatilization is thus prevented as the free passage of the air through the casing maintains the wire at the proper temperature. YVhen, however, an overload in the circuit occurs the rapid heating etfect of the overload Will cause the 'fuse to blow and the pressure resulting from the gases and vapors 'ormed by the blowing of the fuse raises the valve disc 12 SO as to close the opening 15 in the valve cap. The gases are thus expelled downwardly and out of the lower open end of the casing with such velocity as to extinguish any arc which may tend to form along the line of the fuse wire The provision of the valve results in a free movement of the ventilating air along the entire length of the tuse casing and at the same time will operate ai'tomatically upon blowing ot the tuse to expel the resulting gases in the desred direction and with the necessary velocity. The perfect ventilation ot the entire length of tuse wire and casing eliminates any premature heating ot' the wire during normal operation so that no metallc coating can be deposited along the interior of the casing between the terminals or Contacts 6 and 8 and all possibility of short circuiting the fuse wire Letters Patent is:

1. In an expulsion fuse, a hollow cylindrical body, terminals at each end of said body, a valve housing at the upper end of said body and connected to the upper terminal, a plug within said valve body and a fuse wire connected at its upper end to the valve body and at its lower end to the lower terminal.

2. In a Cartridge fus e, a hollow cylindrical body of insulating material, a sleeve like terminal at one end of said body, a valve chamber at the opposite end of said body, an axially movable valve plug in said casing, a vented cap closing said valve casing and a tuse wire at one end connected to said valve casing and at the other to the terminal at the opposite end of said valve body.

3. A Cartridge tuse having in combination a hollow casing open from end to end, a valve plug provided with a valve chamber secured to the upper end of said body and having a vent opening communicating with the interior of said body, a pcrforated cap enclosing said valve chamber and a valve disc in said chamber adapted to normally permit the passage of ventilating air through said chamber and operable upon blowing of said fuse to close the perforaton in said cap so as to 'force the resulting gases downwardly and out of the lower open end of said casing.

4. A Cartridge fuse having in combination a fuse wire, a contact member and a ventilating valve associated with said member and normally open to the atmosphere.

5. An expulsion fuse including a casing open from end to end and provided with upper and lower contact members and means associated with one of said contact members for forcing the gases of explosion out of one end only of said casing.

6. An eXpulsion fuse having a contact member formed so as to permit the passage of air therethrough and a valve in said contact member and operable upon blowing ol said fuse for preventing such passage of air or gas.

7. The combination in an expulsion fuse of' a combined terminal and valve plug having a ventlating opening for the passage of: air therethrough and means operable upon blowing of said fuse for closing said opening.

8. The combination in an eXpulsion fuse of a casing provided with a contact member, a valve plug located in said contact member and provided with an opening for permitting the free circulati on of air through said casing and a terminal tormed on said contact member for connection to a fuse wire.

9. The combination in an eXpulsion fuse ot' a casing, a contact member, a valve plug located in said contact member and provided with an opening for permitting the free circulation of air through said casing, a terminal formed on said contact member for connection to a fuse wire, and a valve disc 'or closing said opening upon blowing of said fuse.

In testimony whereof, I have hereunto subscribed my name this 22nd day ot' July, l925.

NORRIS GHUSTED. 

